Dental dams
Dental dams are a thin sheet of latex used for oral-vaginal sex (cunnilingus) or oral-anal sex (rimming). They come in various colors and flavors. They also come in silicone form for those who are allergic to latex. You can also use flavored, non-oil-based lubricants, to make the experience more, ahem, “tasty.”
Check out how to properly use a dental dam here.